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Degefa T, Yewhalaw D, Yan G. Methods of sampling malaria vectors and their reliability in estimating entomological indices in Africa. J Med Entomol 2024; 61:573-583. [PMID: 38394375 PMCID: PMC11078579 DOI: 10.1093/jme/tjae015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 10/26/2023] [Accepted: 01/29/2024] [Indexed: 02/25/2024]
Abstract
In efforts to intensify malaria control through vector control and hasten the progress towards elimination, the impact of control interventions needs to be evaluated. This requires sampling vector population using appropriate trapping methods. The aim of this article is to critically review methods of sampling malaria vectors and their reliability in estimating entomological indicators of malaria transmission in Africa. The standard methods are human landing catch (HLC), pyrethrum spray catch, and pit shelter for sampling host-seeking, indoor resting, and outdoor resting malaria vectors, respectively. However, these methods also have drawbacks such as exposure of collectors to infective mosquito bites, sampling bias, and feasibility issue. Centers for Disease Control and Prevention (CDC) light traps placed beside human-occupied bed nets have been used as an alternative to the HLC for sampling host-seeking malaria vectors. Efforts have been made to evaluate the CDC light traps against HLC to generate a conversion factor in order to use them as a proxy estimator of human biting rate and entomological inoculation rates in Africa. However, a reproducible conversion factor was not found, indicating that the trapping efficiency of the CDC light traps varies between different geographical locations. Several other alternative traps have also been developed and evaluated in different settings but most of them require further standardization. Among these, human-baited double net trap/CDC light trap combination and mosquito electrocuting trap have the potential to replace the HLC for routine malaria vector surveillance. Further research is needed to optimize the alternative sampling methods and/or develop new surveillance tools based on vector behavior.
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Affiliation(s)
- Teshome Degefa
- School of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
| | - Delenasaw Yewhalaw
- School of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA 92697, USA
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Charlwood JD, Kampango A, Omari M, Okumu F. Simple techniques for a complex problem: Sampling malaria vectors in Africa. Acta Trop 2024; 251:107104. [PMID: 38185187 DOI: 10.1016/j.actatropica.2023.107104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 12/19/2023] [Accepted: 12/19/2023] [Indexed: 01/09/2024]
Abstract
Disease surveillance, including entomological surveillance, serves as the basis for all vector control program activities. How to do this in the most ecologically sensible way, so that the most suitable, naturalistic method, of control for that population can be identified, should be a priority. Here we describe a set of techniques, whose only energy requirement is a torch (flashlight), that can be used to collect both endo and exophagic and endo and exophilic malaria vectors. The data obtained over a number of years from an individual sentinel house in a village in Mozambique and from a village in Cambodia using these kinds of collection techniques, is presented.
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Affiliation(s)
- Jacques Derek Charlwood
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Rua da Junqueira 100, Lisboa, Portugal.
| | - Ayubo Kampango
- Instituto Nacional de Saúde, Vila de Marracuene, EN1 Parcela N 3943, Maputo, Mozambique
| | - Mohamed Omari
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Fredros Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania; School of Biodiversity, One Health, and Veterinary Medicine, University of Glasgow, Glasgow, United Kingdom
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3
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Mawejje HD, Asiimwe JR, Kyagamba P, Kamya MR, Rosenthal PJ, Lines J, Dorsey G, Staedke SG. Impact of different mosquito collection methods on indicators of Anopheles malaria vectors in Uganda. Malar J 2022; 21:388. [PMID: 36536428 PMCID: PMC9761930 DOI: 10.1186/s12936-022-04413-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Methods used to sample mosquitoes are important to consider when estimating entomologic metrics. Human landing catches (HLCs) are considered the gold standard for collecting malaria vectors. However, HLCs are labour intensive, can expose collectors to transmission risk, and are difficult to implement at scale. This study compared alternative methods to HLCs for collecting Anopheles mosquitoes in eastern Uganda. METHODS Between June and November 2021, mosquitoes were collected from randomly selected households in three parishes in Tororo and Busia districts. Mosquitoes were collected indoors and outdoors using HLCs in 16 households every 4 weeks. Additional collections were done indoors with prokopack aspirators, and outdoors with pit traps, in these 16 households every 2 weeks. CDC light trap collections were done indoors in 80 households every 4 weeks. Female Anopheles mosquitoes were identified morphologically and Anopheles gambiae sensu lato were speciated using PCR. Plasmodium falciparum sporozoite testing was done with ELISA. RESULTS Overall, 4,891 female Anopheles were collected, including 3,318 indoors and 1,573 outdoors. Compared to indoor HLCs, vector density (mosquitoes per unit collection) was lower using CDC light traps (4.24 vs 2.96, density ratio [DR] 0.70, 95% CIs 0.63-0.77, p < 0.001) and prokopacks (4.24 vs 1.82, DR 0.43, 95% CIs 0.37-0.49, p < 0.001). Sporozoite rates were similar between indoor methods, although precision was limited. Compared to outdoor HLCs, vector density was higher using pit trap collections (3.53 vs 6.43, DR 1.82, 95% CIs 1.61-2.05, p < 0.001), while the sporozoite rate was lower (0.018 vs 0.004, rate ratio [RR] 0.23, 95% CIs 0.07-0.75, p = 0.008). Prokopacks collected a higher proportion of Anopheles funestus (75.0%) than indoor HLCs (25.8%), while pit traps collected a higher proportion of Anopheles arabiensis (84.3%) than outdoor HLCs (36.9%). CONCLUSION In this setting, the density and species of mosquitoes collected with alternative methods varied, reflecting the feeding and resting characteristics of the common vectors and the different collection approaches. These differences could impact on the accuracy of entomological indicators and estimates of malaria transmission, when using the alternative methods for sampling mosquitos, as compared to HLCs.
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Affiliation(s)
- Henry Ddumba Mawejje
- Infectious Diseases Research Collaboration, Kampala, Uganda. .,London School of Hygiene and Tropical Medicine, London, UK.
| | | | | | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda.,Department of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | | | - Jo Lines
- London School of Hygiene and Tropical Medicine, London, UK
| | - Grant Dorsey
- Department of Medicine, University of California, San Francisco, USA
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Tomas T, Eligo N, Tamiru G, Massebo F. Outdoor and early hour human biting activities of malaria mosquitoes and the suitability of clay pot for outdoor resting mosquito collection in malaria endemic villages of southern Rift Valley, Ethiopia. Parasite Epidemiol Control 2022; 19:e00278. [PMID: 36345433 PMCID: PMC9636569 DOI: 10.1016/j.parepi.2022.e00278] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 08/21/2022] [Accepted: 10/26/2022] [Indexed: 11/07/2022] Open
Abstract
Background Sampling adult Anopheles mosquitoes is important for assessing vector density, estimating the sporozoite infection rate, and quantifying the impact of vector control interventions. The objective of this study was to assess the Anopheles mosquito species composition, and their outdoor and indoor biting activities, and to evaluate the suitability of clay pots for indoor and outdoor resting mosquito collections. Methods Two malaria-endemic villages in the Gamo zone were purposely selected. Forty clay pots were deployed for outdoor resting mosquitoes sampling and another forty for indoor resting sampling. Twenty pit shelters were constructed for outdoor resting mosquito collection. The human landing catch (HLC) technique was employed to collect indoor and outdoor host-seeking mosquitoes in two households in each village. Morphological identification of the Anopheles mosquito was done using an identification key. Enzyme-linked immunosorbent assay technique was used for blood meal origin and circumsporozoite proteins (CSP) test. Speciation of An. gambiae complex was done using polymerase chain reaction. A Chi-square test was used to compare the effectiveness of clay pot and pit shelters for outdoor resting sampling. Results A total of 904 female Anopheles mosquitoes comprising An. gambiae complex, An. pharoensis, An. tenebrosus, An. dencalicus and An. demelloni were sampled. The majority (64%) of them were sampled by the HLC technique. There was a slight difference between the outdoor clay pot (19%) and pit shelter (17%) collection. No Anopheles mosquitoes were collected indoor using clay pots. All mosquitoes were tested for CSPs, but none of them were found to be positive. Anopheles mosquitoes were tending to bite humans outdoor than indoors, and their peak biting hours was 10–11 pm. The human blood meal index of Anopheles mosquitoes was 0.07 from pit shelters and it was 0.04 from clay pots. The bovine blood meal index was 0.45 for mosquitoes from both pit shelters and clay pot collections. Conclusion Anopheles arabiensis was the predominant species and it was tending to bite cattle more than humans. Clay pot could be suitable for outdoor resting mosquito collection, but not for indoor resting species.
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Ondeto BM, Wang X, Atieli H, Orondo PW, Ochwedo KO, Omondi CJ, Otambo WO, Zhong D, Zhou G, Lee MC, Muriu SM, Odongo DO, Ochanda H, Kazura J, Githeko AK, Yan G. Malaria vector bionomics and transmission in irrigated and non-irrigated sites in western Kenya. Parasitol Res 2022; 121:3529-3545. [PMID: 36203064 DOI: 10.1007/s00436-022-07678-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 09/20/2022] [Indexed: 10/10/2022]
Abstract
Irrigation not only helps to improve food security but also creates numerous water bodies for mosquito production. This study assessed the effect of irrigation on malaria vector bionomics and transmission in a semi-arid site with ongoing malaria vector control program. The effectiveness of CDC light traps in the surveillance of malaria vectors was also evaluated relative to the human landing catches (HLCs) method. Adult mosquitoes were sampled in two study sites representing irrigated and non-irrigated agroecosystems in western Kenya using a variety of trapping methods. The mosquito samples were identified to species and assayed for host blood meal source and Plasmodium spp. sporozoite infection using polymerase chain reaction. Anopheles arabiensis was the dominant malaria vector in the two study sites and occurred in significantly higher densities in irrigated study site compared to the non-irrigated study site. The difference in indoor resting density of An. arabiensis during the dry and wet seasons was not significant. Other species, including An. funestus, An. coustani, and An. pharoensis, were collected. The An. funestus indoor resting density was 0.23 in irrigated study site while almost none of this species was collected in the non-irrigated study site. The human blood index (HBI) for An. arabiensis in the irrigated study site was 3.44% and significantly higher than 0.00% for the non-irrigated study site. In the irrigated study site, the HBI of An. arabiensis was 3.90% and 5.20% indoor and outdoor, respectively. The HBI of An. funestus was 49.43% and significantly higher compared to 3.44% for An. arabiensis in the irrigated study site. The annual entomologic inoculation rate for An. arabiensis in the irrigated study site was 0.41 and 0.30 infective bites/person/year indoor and outdoor, respectively, whereas no transmission was observed in the non-irrigated study site. The CDC light trap performed consistently with HLC in terms of vector density. These findings demonstrate that irrigated agriculture may increase the risk of malaria transmission in irrigated areas compared to the non-irrigated areas and highlight the need to complement the existing malaria vector interventions with novel tools targeting the larvae and both indoor and outdoor biting vector populations.
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Affiliation(s)
- Benyl M Ondeto
- Department of Biology, University of Nairobi, Nairobi, 00100, Kenya. .,Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300, Kenya.
| | - Xiaoming Wang
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
| | - Harrysone Atieli
- Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300, Kenya
| | - Pauline Winnie Orondo
- Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300, Kenya.,Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, Nairobi, 00200, Kenya
| | - Kevin O Ochwedo
- Department of Biology, University of Nairobi, Nairobi, 00100, Kenya.,Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300, Kenya
| | - Collince J Omondi
- Department of Biology, University of Nairobi, Nairobi, 00100, Kenya.,Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300, Kenya
| | - Wilfred O Otambo
- Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300, Kenya.,Department of Zoology, Maseno University, Maseno, Kenya
| | - Daibin Zhong
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
| | - Guofa Zhou
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
| | - Ming-Chieh Lee
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
| | - Simon M Muriu
- Department of Biological Sciences, Pwani University, Kilifi, 80108, Kenya
| | - David O Odongo
- Department of Biology, University of Nairobi, Nairobi, 00100, Kenya
| | - Horace Ochanda
- Department of Biology, University of Nairobi, Nairobi, 00100, Kenya
| | - James Kazura
- Center for Global Health and Disease, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Andrew K Githeko
- Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300, Kenya.,Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, 40100, Kenya
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA.
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Yan G, Lee MC, Zhou G, Jiang AL, Degefa T, Zhong D, Wang X, Hemming-Schroeder E, Mukabana WR, Dent AE, King CL, Hsu K, Beeson J, Githure JI, Atieli H, Githeko AK, Yewhalaw D, Kazura JW. Impact of Environmental Modifications on the Ecology, Epidemiology, and Pathogenesis of Plasmodium falciparum and Plasmodium vivax Malaria in East Africa. Am J Trop Med Hyg 2022; 107:5-13. [PMID: 36228918 PMCID: PMC9662213 DOI: 10.4269/ajtmh.21-1254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 07/19/2022] [Indexed: 01/27/2023] Open
Abstract
Food insecurity, recurrent famine, and poverty threaten the health of millions of African residents. Construction of dams and rural irrigation schemes is key to solving these problems. The sub-Saharan Africa International Center of Excellence for Malaria Research addresses major knowledge gaps and challenges in Plasmodium falciparum and Plasmodium vivax malaria control and elimination in malaria-endemic areas of Kenya and Ethiopia where major investments in water resource development are taking place. This article highlights progress of the International Center of Excellence for Malaria Research in malaria vector ecology and behavior, epidemiology, and pathogenesis since its inception in 2017. Studies conducted in four field sites in Kenya and Ethiopia show that dams and irrigation increased the abundance, stability, and productivity of larval habitats, resulting in increased malaria transmission and a greater disease burden. These field studies, together with hydrological and malaria transmission modeling, enhance the ability to predict the impact of water resource development projects on vector larval ecology and malaria risks, thereby facilitating the development of optimal water and environmental management practices in the context of malaria control efforts. Intersectoral collaborations and community engagement are crucial to develop and implement cost-effective malaria control strategies that meet food security needs while controlling malaria burden in local communities.
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Affiliation(s)
- Guiyun Yan
- Program in Public Health, University of California at Irvine, Irvine, California;,Address correspondence to Guiyun Yan, Program in Public Health, Room 3038, Hewitt Hall, University of California, Irvine, CA 92697-4050, E-mail: or James W. Kazura, Center for Global Health & Diseases, Case Western Reserve University, 2109 Adelbert Road Cleveland, OH 44106, E-mail:
| | - Ming-Chieh Lee
- Program in Public Health, University of California at Irvine, Irvine, California
| | - Guofa Zhou
- Program in Public Health, University of California at Irvine, Irvine, California
| | - Ai-Ling Jiang
- Center for Hydrometeorology and Remote Sensing, Department of Civil and Environmental Engineering, University of California at Irvine, Irvine, California
| | - Teshome Degefa
- Department of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
| | - Daibin Zhong
- Program in Public Health, University of California at Irvine, Irvine, California
| | - Xiaoming Wang
- Program in Public Health, University of California at Irvine, Irvine, California
| | | | | | - Arlene E. Dent
- Center for Global Health & Diseases, Case Western Reserve University, Cleveland, Ohio
| | - Christopher L. King
- Center for Global Health & Diseases, Case Western Reserve University, Cleveland, Ohio
| | - Kuolin Hsu
- Center for Hydrometeorology and Remote Sensing, Department of Civil and Environmental Engineering, University of California at Irvine, Irvine, California
| | - James Beeson
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
| | | | - Harrysone Atieli
- School of Public Health and Community Development, Maseno University, Kisumu, Kenya
| | - Andrew K. Githeko
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Delenasaw Yewhalaw
- Department of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia;,Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
| | - James W. Kazura
- Center for Global Health & Diseases, Case Western Reserve University, Cleveland, Ohio;,Address correspondence to Guiyun Yan, Program in Public Health, Room 3038, Hewitt Hall, University of California, Irvine, CA 92697-4050, E-mail: or James W. Kazura, Center for Global Health & Diseases, Case Western Reserve University, 2109 Adelbert Road Cleveland, OH 44106, E-mail:
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Githure JI, Yewhalaw D, Atieli H, Hemming-Schroeder E, Lee MC, Wang X, Zhou G, Zhong D, King CL, Dent A, Mukabana WR, Degefa T, Hsu K, Githeko AK, Okomo G, Dayo L, Tushune K, Omondi CO, Taffese HS, Kazura JW, Yan G. Enhancing Malaria Research, Surveillance, and Control in Endemic Areas of Kenya and Ethiopia. Am J Trop Med Hyg 2022; 107:14-20. [PMID: 36228905 PMCID: PMC9662210 DOI: 10.4269/ajtmh.21-1303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 07/18/2022] [Indexed: 01/27/2023] Open
Abstract
Malaria control programs in Africa encounter daunting challenges that hinder progressive steps toward elimination of the disease. These challenges include widespread insecticide resistance in mosquito vectors, increasing outdoor malaria transmission, lack of vector surveillance and control tools suitable for outdoor biting vectors, weakness in malaria surveillance, and an inadequate number of skilled healthcare personnel. Ecological and epidemiological changes induced by environmental modifications resulting from water resource development projects pose additional barriers to malaria control. Cognizant of these challenges, our International Center of Excellence for Malaria Research (ICEMR) works in close collaboration with relevant government ministries and agencies to align its research efforts with the objectives and strategies of the national malaria control and elimination programs for the benefit of local communities. Our overall goal is to assess the impact of water resource development projects, shifting agricultural practices, and vector interventions on Plasmodium falciparum and P. vivax malaria in Kenya and Ethiopia. From 2017 to date, the ICEMR has advanced knowledge of malaria epidemiology, transmission, immunology, and pathogenesis, and developed tools to enhance vector surveillance and control, improved clinical malaria surveillance and diagnostic methods, and strengthened the capacity of local healthcare providers. Research findings from the ICEMR will inform health policy and strategic planning by ministries of health in their quest to sustain malaria control and achieve elimination goals.
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Affiliation(s)
| | - Delenasaw Yewhalaw
- Department of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia;,Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
| | - Harrysone Atieli
- School of Public Health and Community Development, Maseno University, Kisumu, Kenya
| | | | - Ming-Chieh Lee
- Program in Public Health, University of California at Irvine, Irvine, California
| | - Xiaoming Wang
- Program in Public Health, University of California at Irvine, Irvine, California
| | - Guofa Zhou
- Program in Public Health, University of California at Irvine, Irvine, California
| | - Daibin Zhong
- Program in Public Health, University of California at Irvine, Irvine, California
| | - Christopher L. King
- Center for Global Health & Diseases, Case Western Reserve University, Cleveland, Ohio
| | - Arlene Dent
- Center for Global Health & Diseases, Case Western Reserve University, Cleveland, Ohio
| | | | - Teshome Degefa
- Department of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
| | - Kuolin Hsu
- Center for Hydrometeorology and Remote Sensing, Department of Civil and Environmental Engineering, University of California at Irvine, Irvine, California
| | - Andrew K. Githeko
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Gordon Okomo
- Ministry of Health, Homa Bay County, Homa Bay, Kenya
| | - Lilyana Dayo
- Ministry of Health, Kisumu County, Kisumu, Kenya
| | - Kora Tushune
- Department of Health Management and Policy, Faculty of Public Health, Jimma University, Jimma, Ethiopia
| | | | - Hiwot S. Taffese
- National Malaria Program, Federal Ministry of Health, Addis Ababa, Ethiopia
| | - James W. Kazura
- Center for Global Health & Diseases, Case Western Reserve University, Cleveland, Ohio;,Address correspondence to Guiyun Yan, Program in Public Health, University of California at Irvine, Irvine, CA, E-mail: or James Kazura, Center for Global Health & Diseases, Case Western Reserve University, Cleveland, OH, E-mail:
| | - Guiyun Yan
- Program in Public Health, University of California at Irvine, Irvine, California;,Address correspondence to Guiyun Yan, Program in Public Health, University of California at Irvine, Irvine, CA, E-mail: or James Kazura, Center for Global Health & Diseases, Case Western Reserve University, Cleveland, OH, E-mail:
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Friuli M, Cafarchia C, Cataldo A, Lia RP, Otranto D, Pombi M, Demitri C. Proof of Concept of Biopolymer Based Hydrogels as Biomimetic Oviposition Substrate to Develop Tiger Mosquitoes (Aedes albopictus) Cost-Effective Lure and Kill Ovitraps. Bioengineering (Basel) 2022; 9:267. [PMID: 35877317 PMCID: PMC9312165 DOI: 10.3390/bioengineering9070267] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 06/14/2022] [Accepted: 06/16/2022] [Indexed: 01/03/2023] Open
Abstract
Pest management is looking for green and cost-effective innovative solutions to control tiger mosquitoes and other pests. By using biomimetic principles and biocompatible/biodegradable biopolymers, it could be possible to develop a new approach based on substrates that selectively attract insects by reproducing specific natural environmental conditions and then kill them by hosting and delivering a natural biopesticide or through mechanical action (biomimetic lure and kill approach, BL&K). Such an approach can be theoretically specialized against tiger mosquitoes (BL&K-TM) by designing hydrogels to imitate the natural oviposition site’s conditions to employ them inside a lure and kill ovitraps as a biomimetic oviposition substrate. In this work, the hydrogels have been prepared to prove the concept. The study compares lab/on-field oviposition between standard substrates (absorbing paper/masonite) and a physical and chemically crosslinked hydrogel composition panel. Then the best performing is characterized to evaluate a correlation between the hydrogel’s properties and oviposition. Tests identify a 2-Hydroxyethylcellulose (HEC)-based physical hydrogel preparation as five times more attractive than the control in a lab oviposition assay. When employed on the field in a low-cost cardboard trap, the same substrate is seven times more capturing than a standard masonite ovitrap, with a duration four times longer.
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Jaworski L, Sauer F, Jansen S, Tannich E, Schmidt-Chanasit J, Kiel E, Lühken R. Artificial resting sites: An alternative sampling method for adult mosquitoes. Med Vet Entomol 2022; 36:139-148. [PMID: 34825399 DOI: 10.1111/mve.12559] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 10/29/2021] [Indexed: 06/13/2023]
Abstract
Mosquito collections are commonly conducted with baited traps predominantly attracting host-seeking females. In contrast, resting sites are generally colonized by a broader range of the mosquito population, including a higher proportion of males and blood-engorged females. This study evaluates the sampling success of different artificial resting sites, attached to a deciduous or coniferous tree at different heights. As standard sampling method, carbon dioxide-baited Biogents Sentinel traps (BG traps) were operated in parallel. BG traps caught a higher number of specimens compared to the resting sites. However, the proportion of blood-engorged females and males was higher in resting sites. More Culiseta spp. specimens were collected in resting sites compared to BG traps, but less Aedes spp. specimens. In general, fewer specimens and species were recorded in small resting sites and at top height level compared to medium or large resting sites at medium or ground level. The proportion of males was highest at the ground, while the proportion of engorged females was highest at medium and top level. Due to the higher proportion of blood-engorged females, artificial resting sites are especially useful for studies of host-feeding patterns or xenosurveillance. Low costs and efforts allow a cost-effective increase of the number of resting sites per sampling site to collect more mosquitoes.
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Affiliation(s)
- Linda Jaworski
- Research Group Aquatic Ecology and Nature Conservation, Institute of Biology and Environmental Sciences, School of Mathematics and Science, Carl von Ossietzky University, Oldenburg, Germany
- Department of Arbovirology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Felix Sauer
- Research Group Aquatic Ecology and Nature Conservation, Institute of Biology and Environmental Sciences, School of Mathematics and Science, Carl von Ossietzky University, Oldenburg, Germany
- Department of Arbovirology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Stephanie Jansen
- Department of Arbovirology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Faculty of Mathematics, Informatics and Natural Sciences, Universität Hamburg, Hamburg, Germany
| | - Egbert Tannich
- Department of Arbovirology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | - Jonas Schmidt-Chanasit
- Department of Arbovirology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | - Ellen Kiel
- Research Group Aquatic Ecology and Nature Conservation, Institute of Biology and Environmental Sciences, School of Mathematics and Science, Carl von Ossietzky University, Oldenburg, Germany
| | - Renke Lühken
- Department of Arbovirology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
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Friuli M, Cafarchia C, Lia RP, Otranto D, Pombi M, Demitri C. From tissue engineering to mosquitoes: biopolymers as tools for developing a novel biomimetic approach to pest management/vector control. Parasit Vectors 2022; 15:79. [PMID: 35248154 PMCID: PMC8898440 DOI: 10.1186/s13071-022-05193-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 02/07/2022] [Indexed: 11/13/2022] Open
Abstract
Background Pest management has been facing the spread of invasive species, insecticide resistance phenomena, and concern for the impact of chemical pesticides on human health and the environment. It has tried to deal with them by developing technically efficient and economically sustainable solutions to complement/replace/improve traditional control methods. The renewal has been mainly directed towards less toxic pesticides or enhancing the precision of their delivery to reduce the volume employed and side effects through lure-and-kill approaches based on semiochemicals attractants. However, one of the main pest management problems is that efficacy depends on the effectiveness of the attractant system, limiting its successful employment to semiochemical stimuli-responsive insects. Biomaterial-based and bioinspired/biomimetic solutions that already guide other disciplines (e.g., medical sciences) in developing precision approaches could be a helpful tool to create attractive new strategies to liberate precision pest management from the need for semiochemical stimuli, simplify their integration with bioinsecticides, and foster the use of still underemployed solutions. Approach proposed We propose an innovative approach, called “biomimetic lure-and-kill”. It exploits biomimetic principles and biocompatible/biodegradable biopolymers (e.g., natural hydrogels) to develop new substrates that selectively attract insects by reproducing specific natural environmental conditions (biomimetic lure) and kill them by hosting and delivering a natural biopesticide or through mechanical action. Biomimetic lure-and-kill-designed substrates point to provide a new attractive system to develop/improve and make more cost-competitive new and conventional devices (e.g. traps). A first example application is proposed using the tiger mosquito Aedes albopictus as a model. Conclusions Biomaterials, particularly in the hydrogel form, can be a useful tool for developing the biomimetic lure-and-kill approach because they can satisfy multiple needs simultaneously (e.g., biomimetic lure, mechanical lethality, biocompatibility, and bioinsecticide growth). Such an approach might be cost-competitive, and with the potential for applicability to several pest species. Moreover, it is already technically feasible, since all the technologies necessary to design and configure materials with specific characteristics are already available on the market. Graphical Abstract ![]()
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Affiliation(s)
- Marco Friuli
- Department of Engineering for Innovation, University of Salento, 73100, Lecce, Italy
| | - Claudia Cafarchia
- Department of Veterinary Medicine, University of Bari, Valenzano, Italy
| | | | - Domenico Otranto
- Department of Veterinary Medicine, University of Bari, Valenzano, Italy
| | - Marco Pombi
- Dipartimento Di Sanità Pubblica E Malattie Infettive, Università Di Roma "Sapienza", Rome, Italy.
| | - Christian Demitri
- Department of Engineering for Innovation, University of Salento, 73100, Lecce, Italy
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11
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Jared Owiti Y. Efficacy of a simply resting box baited with crude fruit and leaf ethanol extracts of Phytolaccadodecandra (L' Herit) in capturing and killing of indoor mosquitoes (Diptera: Culicidae) at Korando, Western Kenya. Saudi J Biol Sci 2021; 28:5221-5228. [PMID: 34466100 PMCID: PMC8380997 DOI: 10.1016/j.sjbs.2021.05.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 05/15/2021] [Accepted: 05/18/2021] [Indexed: 11/23/2022] Open
Abstract
Effective capture and elimination of indoor resting mosquito population is important in the fight against mosquito borne diseases. This study aimed at evaluating the efficacy of a simply resting box baited with crude fruit and leaf ethanol extracts of Phytolacca dodecandra in attracting and killing indoor mosquitoes at Korando, Western Kenya. The study was conducted in three phases: pre-intervention, intervention and post intervention. Simple resting boxes made from galvanized wire frame measuring 30 cm × 30 cm × 30 cm, covered in blue and black tunic in and out and lined with carton boards were used. The boxes were baited with socks with strong human odour and 80 ml/100mls (e/w) solution of either crude ethanol fruit or leaf extracts of P. dodecandra, ethanol leaf extracts of Azadiracta indica or Deltamethrin. Deltamethrin and Azadiracta indica were used as positive and water as negative control. The treatments were applied at the intervention phase only. The boxes were left overnight in the houses and mosquitoes collected by 6.30 h. It was observed that more Culicines than Anopheline were captured irrespective of phase or treatment used. Mosquito densities reduced with phase of activity. P. dodecandra leaf extracts killed more mosquitoes than fruit or A. indica leaf extracts though the number were less than that of Deltamethrin or WHO threshold of >80% mortality. In conclusion, the simple resting boxes were effective in collecting and killing indoor mosquitoes though lethality did not matched the WHO threshold. With improved structural set up and use of pure extracts of P. dodecandra, the resting boxes can serve as effective tools for capture, elimination and management of mosquito borne diseases.
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Affiliation(s)
- Yugi Jared Owiti
- School of Science and Technology, University of Kabianga, P. O. Box 20230-20300, Kericho, Kenya
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12
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van de Straat B, Russell TL, Staunton KM, Sinka ME, Burkot TR. A global assessment of surveillance methods for dominant malaria vectors. Sci Rep 2021; 11:15337. [PMID: 34321525 PMCID: PMC8319300 DOI: 10.1038/s41598-021-94656-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/13/2021] [Indexed: 11/26/2022] Open
Abstract
The epidemiology of human malaria differs considerably between and within geographic regions due, in part, to variability in mosquito species behaviours. Recently, the WHO emphasised stratifying interventions using local surveillance data to reduce malaria. The usefulness of vector surveillance is entirely dependent on the biases inherent in the sampling methods deployed to monitor mosquito populations. To understand and interpret mosquito surveillance data, the frequency of use of malaria vector collection methods was analysed from a georeferenced vector dataset (> 10,000 data records), extracted from 875 manuscripts across Africa, the Americas and the Asia-Pacific region. Commonly deployed mosquito collection methods tend to target anticipated vector behaviours in a region to maximise sample size (and by default, ignoring other behaviours). Mosquito collection methods targeting both host-seeking and resting behaviours were seldomly deployed concurrently at the same site. A balanced sampling design using multiple methods would improve the understanding of the range of vector behaviours, leading to improved surveillance and more effective vector control.
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Affiliation(s)
- Bram van de Straat
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia.
| | - Tanya L. Russell
- grid.1011.10000 0004 0474 1797Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia
| | - Kyran M. Staunton
- grid.1011.10000 0004 0474 1797Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia
| | - Marianne E. Sinka
- grid.4991.50000 0004 1936 8948Department of Zoology, University of Oxford, Oxford, UK
| | - Thomas R. Burkot
- grid.1011.10000 0004 0474 1797Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia
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13
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Zhong D, Hemming-Schroeder E, Wang X, Kibret S, Zhou G, Atieli H, Lee MC, Afrane YA, Githeko AK, Yan G. Extensive new Anopheles cryptic species involved in human malaria transmission in western Kenya. Sci Rep 2020; 10:16139. [PMID: 32999365 PMCID: PMC7527330 DOI: 10.1038/s41598-020-73073-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 08/31/2020] [Indexed: 11/09/2022] Open
Abstract
A thorough understanding of malaria vector species composition and their bionomic characteristics is crucial to devise effective and efficient vector control interventions to reduce malaria transmission. It has been well documented in Africa that malaria interventions in the past decade have resulted in major changes in species composition from endophilic Anopheles gambiae to exophilic An. arabiensis. However, the role of cryptic rare mosquito species in malaria transmission is not well known. This study examined the species composition and distribution, with a particular focus on malaria transmission potential of novel, uncharacterized Anopheles cryptic species in western Kenya. Phylogenetic analysis based on ITS2 and COX1 genes revealed 21 Anopheles mosquito species, including two previously unreported novel species. Unusually high rates of Plasmodium sporozoite infections were detected in An. funestus, An. gambiae and eight cryptic rare species. Plasmodium falciparum, P. malariae and P. ovale sporozoite infections were identified with large proportion of mixed species infections in these vectors. This study, for the first time, reports extensive new Anopheles cryptic species involved in the malaria transmission in western Kenya. These findings underscore the importance of non-common Anopheles species in malaria transmission and the need to target them in routine vector control and surveillance efforts.
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Affiliation(s)
- Daibin Zhong
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA.
| | - Elizabeth Hemming-Schroeder
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
| | - Xiaoming Wang
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
| | - Solomon Kibret
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
| | - Guofa Zhou
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
| | - Harrysone Atieli
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Ming-Chieh Lee
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
| | - Yaw A Afrane
- Department of Medical Microbiology, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Andrew K Githeko
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA.
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Degefa T, Yewhalaw D, Zhou G, Atieli H, Githeko AK, Yan G. Evaluation of human-baited double net trap and human-odour-baited CDC light trap for outdoor host-seeking malaria vector surveillance in Kenya and Ethiopia. Malar J 2020; 19:174. [PMID: 32381009 PMCID: PMC7206766 DOI: 10.1186/s12936-020-03244-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 04/23/2020] [Indexed: 11/19/2022] Open
Abstract
Background Surveillance of outdoor host-seeking malaria vectors is crucial to monitor changes in vector biting behaviour and evaluate the impact of vector control interventions. Human landing catch (HLC) has been considered the most reliable and gold standard surveillance method to estimate human-biting rates. However, it is labour-intensive, and its use is facing an increasing ethical concern due to potential risk of exposure to infectious mosquito bites. Thus, alternative methods are required. This study was conducted to evaluate the performance of human-odour-baited CDC light trap (HBLT) and human-baited double net trap (HDNT) for outdoor host-seeking malaria vector surveillance in Kenya and Ethiopia. Methods The sampling efficiency of HBLT and HDNT was compared with CDC light trap and HLC using Latin Square Design in Ahero and Iguhu sites, western Kenya and Bulbul site, southwestern Ethiopia between November 2015 and December 2018. The differences in Anopheles mosquito density among the trapping methods were compared using generalized linear model. Results Overall, 16,963 female Anopheles mosquitoes comprising Anopheles gambiae sensu lato (s.l.), Anopheles funestus s.l., Anopheles pharoensis, Anopheles coustani and Anopheles squamosus were collected. PCR results (n = 552) showed that Anopheles arabiensis was the only member of An. gambiae s.l. in Ahero and Bulbul, while 15.7% An. arabiensis and 84.3% An. gambiae sensu stricto (s.s.) constituted An. gambiae s.l. in Iguhu. In Ahero, HBLT captured 2.23 times as many An. arabiensis and 2.11 times as many An. funestus as CDC light trap. In the same site, HDNT yielded 3.43 times more An. arabiensis and 3.24 times more An. funestus than HBLT. In Iguhu, the density of Anopheles mosquitoes did not vary between the traps (p > 0.05). In Bulbul, HBLT caught 2.19 times as many An. arabiensis as CDC light trap, while HDNT caught 6.53 times as many An. arabiensis as CDC light trap. The mean density of An. arabiensis did not vary between HDNT and HLC (p = 0.098), whereas the HLC yielded significantly higher density of An. arabiensis compared to HBLT and CDC light trap. There was a significant density-independent positive correlation between HDNT and HLC (r = 0.69). Conclusion This study revealed that both HBLT and HDNT caught higher density of malaria vectors than conventional CDC light trap. Moreover, HDNT yielded a similar vector density as HLC, suggesting that it could be an alternative tool to HLC for outdoor host-seeking malaria vector surveillance.
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Affiliation(s)
- Teshome Degefa
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia. .,Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.
| | - Delenasaw Yewhalaw
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia.,Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Guofa Zhou
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
| | - Harrysone Atieli
- School of Public Health and Community Development, Maseno University, Kisumu, Kenya
| | - Andrew K Githeko
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
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Githinji EK, Irungu LW, Ndegwa PN, Machani MG, Amito RO, Kemei BJ, Murima PN, Ombui GM, Wanjoya AK, Mbogo CM, Mathenge EM. Species Composition, Phenotypic and Genotypic Resistance Levels in Major Malaria Vectors in Teso North and Teso South Subcounties in Busia County, Western Kenya. J Parasitol Res 2020; 2020:3560310. [PMID: 32411419 DOI: 10.1155/2020/3560310] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 11/12/2019] [Accepted: 12/11/2019] [Indexed: 12/13/2022] Open
Abstract
Introduction Knockdown resistance (kdr) is strongly linked to pyrethroid insecticide resistance in Anopheles gambiae in Africa, which may have vital significance to the current increased use of pyrethroid-treated bed net programmes. The study is aimed at determining species composition, levels of insecticide resistance, and knockdown patterns in Anopheles gambiae sensu lato in areas with and areas without insecticide resistance in Teso North and Teso South subcounties, Western Kenya. Materials and Methods For WHO vulnerability tests, mosquito larvae were sampled using a dipper, reared into 3-5-day-old female mosquitoes (4944 at 100 mosquitoes per insecticide) which were exposed to 0.75% permethrin, 0.05% deltamethrin, and 0.1% bendiocarb using the WHO tube assay method. Species identification and kdr East gene PCRs were also performed on randomly selected mosquitoes from the collections; including adult mosquitoes (3448) sampled using standard collection methods. Results Anopheles gambiae sensu stricto were the majority in terms of species composition at 78.9%. Bendiocarb caused 100% mortality while deltamethrin had higher insecticidal effects (77%) on female mosquitoes than permethrin (71%). Susceptible Kengatunyi cluster had higher proportion of An. arabiensis (20.9%) than resistant Rwatama (10.7%). Kengatunyi mosquitoes exposed to deltamethrin had the highest KDT50 R of 8.2. Both Anopheles gambiae sensu stricto and Anopheles arabiensis had equal S allelic frequency of 0.84. Indoor resting mosquitoes had 100% mortality rate after 24 h since exposure. Overall SS genotypic frequency in Teso North and Teso South subcounties was 79.4% against 13.7% homozygous LL genotype and 6.9% heterozygous LS genotype. There was a significant difference (ρ < 0.05) in S allele frequencies between Kengatunyi (0.61) and Rwatama (0.95). Mosquito samples collected in 2013 had the highest S allelic frequency of 0.87. Discussion. Most likely, the higher the selection pressure exerted indoors by insecticidal nets, the higher were the resistance alleles. Use of pyrethroid impregnated nets and agrochemicals may have caused female mosquitoes to select for pyrethroid resistance. Different modes of action and chemical properties in different types of pyrethroids aggravated by a variety of edaphic and climatic factors may have caused different levels of susceptibility in both indoor and outdoor vectors to pyrethroids and carbamate. Species composition and populations in each collection method may have been influenced by insecticide resistance capacity in different species. Conclusions and Recommendations. Both phenotypic and genotypic insecticide resistance levels have been confirmed in Teso North and Teso South subcounties in Western Kenya. Insecticide resistance management practices in Kenya should be fast tracked and harmonized with agricultural sector agrochemical-based activities and legislation, and possibly switch to carbamate use in order to ease selection pressure on pyrethroids which are useable in insecticidal nets and indoor residual spray due to their low human toxicity. The implication of such high resistance levels in mosquitoes collected in Teso subcounties is that resistance is likely to persist and or even increase if monomolecules of permethrin and deltamethrin or both continue to be used in all net- and nonnet-based mosquito control purposes. Usage of mutually reinforcing piperonyl butoxide (PBO) that prohibits particular enzymes vital in metabolic activities inside mosquito systems and has been integrated into pyrethroid-LLINs to create pyrethroid-PBO nets is an extremely viable option.
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